It's not just Piper. EVERY certified low wing, single door 4 place model
since WWII has the same configuration. Presumably, designers give at least
SOME thought to the ergonomics of door location, so the fact that Beech,
Piper, Mooney Bellanca, and Cessna (300-series twins) all came up with the
same conclusion suggests that there is some rational basis, even if it's
only "tradition".

--
-Elliott Drucker